This document reviews nonwoven acoustic textiles. It discusses how fiber parameters like size, type, and cross-section influence sound absorption properties. Process parameters like web formation and bonding methods are also important. Physical properties of nonwovens that impact sound absorption include thickness, density, airflow resistance, porosity, tortuosity, and the presence of an air gap behind the material. Fiber entanglement creates tortuous pathways that convert sound energy to heat through friction, improving absorption. Low density materials better absorb low frequencies, while denser structures perform better at high frequencies.